Regular physical activity has been shown to enhance physical function and health-related quality of life and reduce morbidity and mortality among older adults. Unfortunately, compliance rates to physical activity programs are distressingly low, even among asymptomatic populations. Many traditional exercise interventions do not provide the self-regulatory skills necessary for long-term behavioral change. These issues become more prominent as the population of older Americans continues to increase. Although only a small percentage of older adults engage in habitual physical activity, there are episodic charity events involving moderate physical activity that attract large numbers of participants of all age ranges. These actions are a form of prosocial behavior, defined as voluntary, intentional behavior that results in benefits for another. The opportunity to help others seems to be a motive to inspire these individuals to at least engage in acute moderate physical activity. In previous pilot work (Section 4.1.a), we found that participants randomized into a prosocial behavior physical activity group demonstrated increased physical activity at 3 months compared to those in a standard exercise group. Our current research question contemplates whether prosocial behavior may be implemented as a viable behavioral incentive for long-term physical activity. Therefore, the primary aim of this investigation is to determine the feasibility of conducting a 9-month prosocial behavior intervention to increase physical activity among 80 underactive older adults. To our knowledge, the use of prosocial behavior as a motivational tool for physical activity has not been investigated, and represents a novel approach. The PBPA program will allow participants to earn boxes of food for donation to the Second Harvest Food Bank of Northwest North Carolina based upon their weekly physical activity. Other specific aims include determining the ability to successfully recruit participants into the study, the ability of participants to adhere to the PBPA program, and the ability to retain participants throughout the study. If successful, preliminary data from this study will be used to seek R01 funding to conduct a fully powered, longitudinal trial.